1. Field of the Invention
The present invention relates to a heat-resistant laminated conveyer belt, particularly a heat-resistant laminated conveyer belt to be used for a corrugated board production machine.
2. Description of the Related Art
For example, a heat-resistant laminated conveyer belt having a configuration shown in FIGS. 1A and 1B is used for the corrugated board production machine (for example, Patent Literature 1). In this regard, FIG. 1A is a front view of the conveyer belt and FIG. 1B is a cross-sectional view along with line IB-IB of FIG. 1A.
A reinforcement layer 1 in the drawings is mainly responsible for mechanical strength of the belt. An abrasion-resistant layer 3 is formed on the reinforcement layer 1 through an adhesive layer 2 composed of a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA resin) film. Here, the abrasion-resistant layer 3 has a function for providing good bonding characteristics by applying abrasion resistance, mold-release characteristics, and hardness to the belt.
The reinforcement layer 1 is obtained by, for example, repeating several times a process of impregnating a woven fabric obtained by plain weaving an aramid fiber in a tetrafluoroethylene resin (PTFE resin) dispersion and drying and sintering the fabric. Alternatively, the reinforcement layer is obtained by repeating several times a process of impregnating a woven fabric obtained by circular knitting an aramid fiber in a PTFE resin dispersion and drying and sintering the fabric.
A four-layered conveyer belt in which an adhesive layer, an abrasion-resistant layer, and a sheet layer of a mixture obtained by mixing an aramid fiber and a PTFE resin are formed on the periphery side of the reinforcement layer and a three-layered conveyer belt in which a material obtained by coating an aramid fiber with polyimide and PFA resin is used as a wear-proof layer are suggested (for example, Patent Literature 2).
Further, a three-layered conveyer belt composed of a core, an adhesive layer, and a woven fabric as a surface layer is also suggested (for example, Patent Literature 3).
The heat-resistant laminated conveyer belt is used, for example, as a pressurizing belt in a process of producing a corrugated board as shown in FIG. 2. In FIG. 2, a corrugated board is produced by using a bonding method based on a pressurizing belt.
An upper roll 11 is engaged with a lower roll 12. Two pressure rolls 13a and 13b are arranged on the upper roll 11 adjacent to the upper roll 12. A 10 pressurizing belt 14 in an endless form is mounted on the pressure rolls 13a and 13b. 
In the method of FIG. 2, a single-faced corrugated board sheet 17 is produced by passing a core paper 15 between the upper roll 11 and the lower roll 12 and between the upper roll 11 and the pressurizing belt 14 in a direction of an arrow X, passing a corrugated board liner 16 between the upper roll 11 and the pressurizing belt 14 in a direction of an arrow Y, and integrating the core paper 15 with the corrugated board liner 16 by an adhesive paste (not shown) to be applied onto the convex portion of the core paper 15 with a concavo-convex shape. When a laminate of the core paper 15 and the corrugated board liner 16 is passed between the upper roll 11 and the pressurizing belt 14, a pressure indicated by an arrow Z from the pressure rolls 13a and 13b through the pressurizing belt 14 is configured to be applied on the laminate.
Recently, the process of producing a corrugated board based on the pressurizing belt becomes a global mainstream in the industry. In such a circumstance, the pressurizing belt is used under severe conditions of hot environment, high-speed running, high tensile strength, high vibration, and adhesion of the adhesive paste. There is a demand for the pressurizing belt to correspond to the quality of paper for corrugated boards in each country. However, due to poor overall strength of the belt itself and poor surface hardness including abrasion resistance, a belt having the quality of material and the configuration does not sufficiently correspond to it at present.